N-terminal acetylation is critical for forming a-helical oligomer of a-synuclein

The aggregation of the protein a-synuclein (AS) is critical to the pathogenesis of Parkinson's disease. Although generally described as an unstructured monomer, recent evidence suggests that the native form of AS may be an a-helical tetramer which resists aggregation. Here, we show that N-terminal acetylation in combination with a mild purification protocol results in an oligomeric form of AS with partial a-helical structure. N-terminal acetylation of AS could have important implications for both the native and pathological structures and functions of AS. Through our demonstration of a recombinant expression system, our results represent an important step toward biochemical and biophysical characterization of this potentially important form of AS.